9.25 focuser question

[matt]

Guys

Can anyone tell me what causes the focus knob that comes standard with the Celestron 9.25 to "stiffen" or tighten up at exactly the same point in its rotation?

I've made sure the rubber knob isn't pressing up against the outside base plate. As far as I can tell it's not coming into contact with that at all.

So it must me something internal? For most of its 360 degrees it turns quite loose, but then at the same point in every turn it stiffens up a bit.

Many thanks

[Harpspitfire]

mines quite smooth all the time, my guess is it shouldnt be that way- i wouldnt know what causes your tightness though

[Robert_T]

Hi Matt, can't say I've noticed this on mine either... then again these days I don't use the knob much just get it close to focus and use the moto-focus from there. Given the way mirror shift focussing works, sliding the mirro up and down on a central post it might be a large blob of grease